Chemical Composition of The Protoplasm And Its Significans

Protoplasm of the nucleus contains various substances. these substances are essential for biological, metabolic, genetic etc. function.

It has been found that Protoplasm consists 34 elements, out of which 12 elements are supposed to be present universally.
99 % of the protoplasm is made of 4 basic elements , that is oxygen, carbon, hydrogen and nitrogen . Hence these basic elements are called as major constituents of protoplasm.
Remaining 1 % of the protoplasm is made of 8 other elements, that is sulphur, phosphorus, potassium, iron, magnesium, calcium, sodium and chloride. Hence these elements are called as trace elements.
Few other elements such as boron, fluorine, manganese, silicon, molybdenum and zinc are also present in a very minute form.

A. Inorganic Constituents

Water , salts and gases are the inorganic constituents of protoplasm.

i. Water

The percentage of water in the protoplasm of an organism depends directly on the age, metabolic activities and habitat.
All Biological activities of the protoplasm is performed in the presence of water.
It serves as a natural solvent for various minerals and as a medium of dispersion for colloidal of protoplasm.
The approximate percentage of water in protoplasm is about 85 – 90 % , which is found in two forms – free water and bound water.

95 % of the total cellular water is free water in which various inorganic substances and organic compounds are found dissolved.
Remaining 5 % of the total cellular water is bound water which is loosely linked with protein molecules by hydrogen bond or other forces.

High surface tension of the water renders the cell more susceptible to temperature fluctuations.

ii. Salts

The trace elements of the protoplasm, which are present in 1 % of the protoplasm, makes salts in the cell. These salts are electrolytes and occur in ionic states as described above.

iii. Gases

Carbon di oxide and Oxygen are generally found , which are the results of metabolic activities & respiration.

B. Organic Constituents

Various organic constituents are found in protoplasm, whose list is as follows –

1. Proteins

2. Carbohydrates

3. Lipids

4. Enzymes

5. Regulatory substances

a. Hormones

b. Vitamins

6. Nucleic acids

1. Proteins

Proteins are the chains of amino acids linked by peptide bonds. These are the polymers of amino acids.
These molecules are large , composed of thousands of atoms. Hence their molecular weight is very high.
Proteins are the most important organic compounds found in protoplasm in one form or other.
Proteins consists 14 – 16 % of the total weight of the protoplasm.
The proteins with lipids and water represent the main constituents of protoplasm.
Proteins consists of C , O , H & N , which may various combinations with phosphorus in nucleic acids and with S , Mg , Fe , etc.
They generally remain in a colloidal state.
The characteristic of an amino acid is described by the presence of an amino group ( - NH2 ) and the carboxyl group ( - COOH ). The amino group is basic and the carboxyl group is acidic in nature.
On heating proteins become broken into their components – amino acids.
The cytoplasm contains about 22 types of amino acids found freely. They constitute the amino acid pool.
All types of proteins such as - Simple proteins, conjugated proteins and derived proteins are found in Protoplasm.

2. Carbohydrates

These are the second most common substances of protoplasm after proteins.
In plants carbohydrates consists 14 – 16 % of the total weight of the protoplasm, while in animals it consists only 1 – 3 % .
These are the main source of energy for all living being.
They are composed of C , H and O . Hydrogen and Oxygen are present in 2 : 1 ratio as in water.
After hydrolysis, they form glucose and water. The glucose is converted glycogen as a storage product.
In plants they form important constituents of cell wall and serve as supporting elements, while in animals tissues have fever carbohydrates.
There are three types of carbohydrates – monosaccharide, oligosaccharide and polysaccharide.

Monosaccharide and oligosaccharide are commonly known as sugars. These are soluble in water , can be crystallized and easily pass through the dialyzing membrane.
Polysaccharide neither crystallizes nor passes through the dialyzing membrane.

3. Lipids

Lipids are also the storage products, which supplies the energy to the cell.
Lipids are formed from C , H and O but the quantity of oxygen is less in comparison to carbohydrates.
Lipids are also colloids means it is insoluble in water but soluble in organic solvents like ether, chloroform, benzene etc.
They are several types, mainly – simple lipids, complex lipids, derived lipids and carotenoids.

4. Enzymes

Enzymes are the complex proteins found in protoplasm. These are the largest and most specialized class of proteins molecules.
They also have the colloidal nature.
Enzymes act as a biocatalyzers in various metabolic activities.
More than thousand different enzymes have been identifies.
The enzymes may be intracellular or extracellular.
Enzymes play important role in various cellular activities.
Coenzymes : some enzymes require small non – protein components for their activity, these components are called as cofactors. Cofactor is also termed as prosthetic group which is bound very tightly by covalent linkage to the enzyme protein. Such enzymes are called coenzymes.
Isoenzymes : Isoenzymes are multiple forms of an enzyme which differ by the minor variations in amino acid composition and regulations.

5. Regulatory Substances

Regulatory substances are complex organic secretions which maintain the metabolic rate of the cells in an orderly manner. these include hormones and vitamins.

a. Hormones

Hormones are the secretion of the protoplasm of endocrine cells which constitute the ductless glands.
The hormones present in the cytoplasm of the cells regulate the synthesis of m-RNA, enzymes and various other intracellular physiological activities.
Different glands secrets different hormones in a very small quantities and poured into blood which carries them to organs.

b. Vitamins

Vitamins are not present in the cytoplasm of the cell.
It obtained from the environment along with food etc.
Vitamins are essential for normal growth, metabolism and maintenance of vigour.
Deficiency of vitamins reduces the rates of cellular metabolism and may causes deficiency disease.
There are many types of vitamins – vitamin A , Vitamin B ( complex ) , vitamin C , Vitamin D , vitamin E , vitamin K , vitamin P .

6. Nucleic Acids

These are the important organic substances found in nucleus and cytoplasm.
They control the important biosynthetic activities of the cell and carry hereditary information from generation to generation.

A Double Stranded DNA

Nucleic acid are associated with the chromosomes and transmit various information to cytoplasm.
There are two types of nucleic acids are present – RNA ( Ribonucleic acid ) and DNA (Deoxyribonucleic acid ).
Deoxyribonucleic acid ( DNA ) is the major part of genetic information.
The synthesis of proteins through transcription is performed by the nucleic acids.

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